[NET] Generalise tcp_listen_opt

This chunks out the accept_queue and tcp_listen_opt code and moves
them to net/core/request_sock.c and include/net/request_sock.h, to
make it useful for other transport protocols, DCCP being the first one
to use it.

Next patches will rename tcp_listen_opt to accept_sock and remove the
inline tcp functions that just call a reqsk_queue_ function.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 46 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 1c29feb6b35f..b85a46dd40a0 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -316,7 +316,7 @@ EXPORT_SYMBOL(tcp_enter_memory_pressure);
 static __inline__ unsigned int tcp_listen_poll(struct sock *sk,
                                                poll_table *wait)
 {
-        return tcp_sk(sk)->accept_queue ? (POLLIN | POLLRDNORM) : 0;
+        return !reqsk_queue_empty(&tcp_sk(sk)->accept_queue) ? (POLLIN | POLLRDNORM) : 0;
 }
 
 /*
@@ -462,28 +462,15 @@ int tcp_listen_start(struct sock *sk)
 {
         struct inet_sock *inet = inet_sk(sk);
         struct tcp_sock *tp = tcp_sk(sk);
-        struct tcp_listen_opt *lopt;
+        int rc = reqsk_queue_alloc(&tp->accept_queue, TCP_SYNQ_HSIZE);
+
+        if (rc != 0)
+                return rc;
 
         sk->sk_max_ack_backlog = 0;
         sk->sk_ack_backlog = 0;
-        tp->accept_queue = tp->accept_queue_tail = NULL;
-        rwlock_init(&tp->syn_wait_lock);
         tcp_delack_init(tp);
 
-        lopt = kmalloc(sizeof(struct tcp_listen_opt), GFP_KERNEL);
-        if (!lopt)
-                return -ENOMEM;
-
-        memset(lopt, 0, sizeof(struct tcp_listen_opt));
-        for (lopt->max_qlen_log = 6; ; lopt->max_qlen_log++)
-                if ((1 << lopt->max_qlen_log) >= sysctl_max_syn_backlog)
-                        break;
-        get_random_bytes(&lopt->hash_rnd, 4);
-
-        write_lock_bh(&tp->syn_wait_lock);
-        tp->listen_opt = lopt;
-        write_unlock_bh(&tp->syn_wait_lock);
-
         /* There is race window here: we announce ourselves listening,
          * but this transition is still not validated by get_port().
          * It is OK, because this socket enters to hash table only
@@ -500,10 +487,7 @@ int tcp_listen_start(struct sock *sk)
         }
 
         sk->sk_state = TCP_CLOSE;
-        write_lock_bh(&tp->syn_wait_lock);
-        tp->listen_opt = NULL;
-        write_unlock_bh(&tp->syn_wait_lock);
-        kfree(lopt);
+        reqsk_queue_destroy(&tp->accept_queue);
         return -EADDRINUSE;
 }
 
@@ -515,18 +499,16 @@ int tcp_listen_start(struct sock *sk)
 static void tcp_listen_stop (struct sock *sk)
 {
         struct tcp_sock *tp = tcp_sk(sk);
-        struct tcp_listen_opt *lopt = tp->listen_opt;
-        struct request_sock *acc_req = tp->accept_queue;
+        struct tcp_listen_opt *lopt;
+        struct request_sock *acc_req;
         struct request_sock *req;
         int i;
 
         tcp_delete_keepalive_timer(sk);
 
         /* make all the listen_opt local to us */
-        write_lock_bh(&tp->syn_wait_lock);
-        tp->listen_opt = NULL;
-        write_unlock_bh(&tp->syn_wait_lock);
-        tp->accept_queue = tp->accept_queue_tail = NULL;
+        lopt = reqsk_queue_yank_listen_sk(&tp->accept_queue);
+        acc_req = reqsk_queue_yank_acceptq(&tp->accept_queue);
 
         if (lopt->qlen) {
                 for (i = 0; i < TCP_SYNQ_HSIZE; i++) {
@@ -1867,11 +1849,11 @@ static int wait_for_connect(struct sock *sk, long timeo)
                 prepare_to_wait_exclusive(sk->sk_sleep, &wait,
                                           TASK_INTERRUPTIBLE);
                 release_sock(sk);
-                if (!tp->accept_queue)
+                if (reqsk_queue_empty(&tp->accept_queue))
                         timeo = schedule_timeout(timeo);
                 lock_sock(sk);
                 err = 0;
-                if (tp->accept_queue)
+                if (!reqsk_queue_empty(&tp->accept_queue))
                         break;
                 err = -EINVAL;
                 if (sk->sk_state != TCP_LISTEN)
@@ -1894,7 +1876,6 @@ static int wait_for_connect(struct sock *sk, long timeo)
 struct sock *tcp_accept(struct sock *sk, int flags, int *err)
 {
         struct tcp_sock *tp = tcp_sk(sk);
-        struct request_sock *req;
         struct sock *newsk;
         int error;
 
@@ -1905,37 +1886,31 @@ struct sock *tcp_accept(struct sock *sk, int flags, int *err)
          */
         error = -EINVAL;
         if (sk->sk_state != TCP_LISTEN)
-                goto out;
+                goto out_err;
 
         /* Find already established connection */
-        if (!tp->accept_queue) {
+        if (reqsk_queue_empty(&tp->accept_queue)) {
                 long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
 
                 /* If this is a non blocking socket don't sleep */
                 error = -EAGAIN;
                 if (!timeo)
-                        goto out;
+                        goto out_err;
 
                 error = wait_for_connect(sk, timeo);
                 if (error)
-                        goto out;
+                        goto out_err;
         }
 
-        req = tp->accept_queue;
-        if ((tp->accept_queue = req->dl_next) == NULL)
-                tp->accept_queue_tail = NULL;
-
-        newsk = req->sk;
-        sk_acceptq_removed(sk);
-        __reqsk_free(req);
+        newsk = reqsk_queue_get_child(&tp->accept_queue, sk);
         BUG_TRAP(newsk->sk_state != TCP_SYN_RECV);
-        release_sock(sk);
-        return newsk;
-
 out:
         release_sock(sk);
+        return newsk;
+out_err:
+        newsk = NULL;
         *err = error;
-        return NULL;
+        goto out;
 }
 
 /*